Best thermostatic bath shower mixer taps for low pressure - Bristan or Mira (magni-flo technology)?

amaraz8

I'm looking to get thermostatic bath shower mixer taps to replace a current one that's not thermostatic. We have low water pressure so not the best flow rate, but useable (gravity fed so cold water tank in loft and hot water in airing cupboard).

I was looking at the Mira ones which have Mira Magni-flo technology (specifically the Mira 'Atom' or 'Assist' BSM models as these can be installed on the bath deck) - the magni-flo technology apparently delivers up to 3x more flow, even at low pressure. Anyone experience the better 'flow' that Mira claims it to offer or is this just marketing tactics? Or will a Bristan thermostatic bath shower mixer tap be just as similar in terms of flow? (e.g. Bristan AS2 THBSM). Any help would be appreciated!

neilmcl

Do you like to have hot baths, because a thermostatic bath/shower mixer isn't going to give you them, especially when limited with low water pressure. Thermostatic mixers are safety limited to around 45C so you'll struggle getting a bath really hot when using them.

nofoollikeold

I suspect the key phrase is "...  UP to 3x more flow than other mixer showers...".  Make a decent shower, compare it with a rubbish one, and there is your comparison.  

amaraz8

neilmcl said:

Do you like to have hot baths, because a thermostatic bath/shower mixer isn't going to give you them, especially when limited with low water pressure. Thermostatic mixers are safety limited to around 45C so you'll struggle getting a bath really hot when using them.

Thanks I wasn't aware of that, so that's really helpful....I do like hot baths so the thermostatic bath shower mixer idea would be out then! But could I install a normal thermostatic shower mixer (not the bath mixer tap - the bar type ones) and then just install a normal mixer tap on the bath?

NSG666

amaraz8 said:

neilmcl said:

Do you like to have hot baths, because a thermostatic bath/shower mixer isn't going to give you them, especially when limited with low water pressure. Thermostatic mixers are safety limited to around 45C so you'll struggle getting a bath really hot when using them.

Thanks I wasn't aware of that, so that's really helpful....I do like hot baths so the thermostatic bath shower mixer idea would be out then! But could I install a normal thermostatic shower mixer (not the bath mixer tap - the bar type ones) and then just install a normal mixer tap on the bath?

Current Building Regs say that the water coming out of bath taps must be limited to 48 degrees C by the use of a thermostatic mixing valve. BR doesn't apply to you but at least you can see what people in newer houses are limited to. I've fitted thermostatic bath shower mixers on numerous occasions and not being able to run a hot enough bath has never been fed back to me.

If your cold bath tap is fed from the mains rather than the tank in the loft I don't think a thermostatic bath shower mixer will work.

The Mira is preferable to the Bristan as it only need 0.1bar as opposed to 0.5. (For every metre your cold water storage tank is above the shower head you gain 0.1 bar so if your tank is in the loft and your shower is on the 1st floor / ground in a bungalow then you could have less than 0.1 but possibly up to 0.3)

I've fitted Mira showers that work at 0.1bar on low pressure balanced systems and the customer has been happy with them but they have pretty low flow rates.